Hazards Associated With Flying at Night - PowerPoint PPT Presentation

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Hazards Associated With Flying at Night

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  1. Transport Canada Transports Canada Hazards Associated WithFlying at Night Presented by Name Transport Canada, System Safety

  2. Main Causes of Night Accidents • VFR-into-IMC • CFIT

  3. CARs • CAR 602.115 three mile visibility for night VFR • CAR 703.27 prohibits en route night VFR at less than 1000 ft above the highest obstacle along specific routes

  4. The Eye

  5. Night vision Two blind spots Lack of colour vision Reduced acuity Reduced depth perception Night myopia Visual hypoxia Night blindness Effects of aging Carbon monoxide, alcohol, drugs, fatigue, smoking Factors that Affect ourNight Vision

  6. Night Vision • Process requires about 30 min • Rods become adjusted to darkness • Off-centre viewing important during night flights • Smoking, carbon monoxide, hypoxia, certain drugs adversly affect night vision • Avoid bright lights to preserve night vision • Red light preserves night vision but severley distorts colours

  7. Two Blind Spots • Physiological blind spot • Central blind Spot • Use an off-centre scanning technique

  8. Lack of Colour Vision • Rod vision is unable to discriminate colours

  9. Reduced Acuity • Central vision blindness at night • High rod-to-optic nerve fiber ratio reduces acuity

  10. Reduced Depth Perception • Rod vision and pupil dilation reduces depth perception

  11. Night Myopia • Shortsightedness occurs during dark focus • Periodically change focus distance

  12. Visual Hypoxia • The retina of the eye is more sensitive to hypoxia than any part of our body • One of the first symptoms of hypoxia is a decrease in night vision • Effects most noticeable starting at 5000’ above ground level to which you are acclimated • Smokers are much more susceptible to hypoxia due to the build-up of carbon monoxide in their blood

  13. Night Blindness • Functionally blind due to pigment deficiency in rods • Night blindness induced within 60 days on diet lacking vitamin A

  14. Pupil size decreases Range of eye focus is reduced Visual acuity is reduced Colour discrimination becomes more difficult It takes longer to process visual information in general Sensitivity to glare increases Takes longer to read under dim light conditions Effects of Aging

  15. Night Illusions & Limitations Illusions • Autokinesis (objects appear to shift) • False reference (stars or lights near horizon) • Venus and sirius (false aircraft) • Night myopia (dilation, inability to focus) • Somatogravic (acceleration with pitch) Limitations • Night blind spot (rods & cones, stars, etc) • Light to dark adaptation (2 hours)

  16. Focused Scan Problems: Night • Night blind spot (A.I.P. AIR 3.7) • centre portion of eye is blind at night • Night Scan • look 10-150away from what you try to see • night vision is affected by altitude • drugs, alcohol, smoking and fatigue adversely affect night and day vision

  17. Pre-Flight Planning • Route Study • Weather Conditions • Equipment • Alternate Plan

  18. Ground Operations • Taxi speed illusion • Geographic disorientation • Risk of collision

  19. Take off and Climb • Lining up • Take off into the black-hole • Somatogravic illusion

  20. Cruise • Ability to detect and monitor weather • Terrain detection • Geographic disoriention

  21. VMC into IMC Conditions 178 Seconds

  22. Approach and Landing • Runway detection • Black-hole approach • Effects of runway slope • Runway dimensions • Atmospheric conditions • Runway lighting

  23. Black-hole Diagram Arc Radius 3 degree glidescope Arc of Constant Visual Angle

  24. Be alert for the black-hole illusion if you observe these conditions • An airport that is on the near side of a brightly lit city with few or no terrain features or lights between you and the airport • An airport that is on the coast or lake shore • An airport in a very sparsely settled areas

  25. Fatigue Induces Human Error

  26. Preventative Measures • Recognize normal human visual limitations involved know what they are and circumstances they are most likely to occur • Learn which airports are conducive to visual illusions at night and use the Canada Flight Supplement (CFS) for more information and restrictions during hours of darkness • Use flight instruments for approaches especially those that provide glide path information (i.e., ILS, DME readouts and altimeter) • Use airport aids to vision (i.e., VASIS, T-VASIS)

  27. More Preventative Measures • Avoid visual long straight-in approaches (overfly airport if necessary) • For geographic disorientation use radio navigation and GPS if fitted • Pay attention to alert devices (radio, altimeter, GPWS) • Double check your own expectations and perceptions • Ensure adequate sleep and nutrition